Life Cycle Assessment and Circular Economy in Emerging Green and Sustainable Energy Sectors: A Critical Review

Emerging green and sustainable energy (GSE) sectors, such as electric vehicles (EVs) and green hydrogen (GH) are crucial for achieving the global decarbonization goals. This study provides critical insights from 157 articles published in Scopus and Web of Science databases by employing PRISMA approach. It was found that combining circular economy (CE) with life cycle assessment (LCA) offers clear sustainability benefits though effective evaluation of environmental impacts. Major identified gaps are methodological variations, geographical concentration of CE-LCA studies, limited focus on real-world applications, and non-inclusion of socio-economic dimensions. The study highlights the role of CE-LCA in resource efficiency, particularly in battery recycling and GH production. Furthermore, adoption of methodological harmonization and policy-aligned frameworks were found to significantly influence the practical application of CE-LCA models. Notably, second-life applications of batteries and waste-to-hydrogen systems were found to be promising strategies to reduce the global warming potential and improve the circularity outcomes. The study recommends the standardization of CE-LCA frameworks, development of region-specific life cycle inventory databases, and their inclusion into policy and regulatory frameworks. Additionally, the integration of artificial intelligence, machine learning, and internet of things into CE-LCA practices is essential to enhance data quality, enable real-time monitoring, and support sustainability assessments.